1,205 research outputs found

    The communicative wheel: Symptom, signal, and model in multimodal communication

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    This paper addresses the need for a model of communication with a new, holistic conception of language within it. The resultant process model is called the Communicative Wheel. It consists of three communicative products: the sender’s input corresponding to his/her experience of a situation (symptom), an output corresponding to a piece of information to the receiver (signal), and the receiver’s intake corresponding to a description of the situation referred to (model). What the model of the wheel suggests, is that the understanding of ‘utterance’ as symbolic needs to be replaced by an understanding of it as indexical

    The Effect of the Housing Boom on Farm Land Values via Tax-Deferred Exchanges

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    This project examines Section 1031 of the Internal Revenue Code and agriculture land exchanges. Stakeholders in rural communities and agriculture are particularly interested in Section 1031 because the recent growth in transaction values of farmland may have, in part, been stimulated by Section 1031 land exchanges. Further, although many have speculated that such exchanges are widely used, little empirical research exists about the provision. We examine the theory of exchanges and develop a theoretical premium value for exchanges. We also present the first evidence of like-kind exchanges involving farmland using Federal tax data.Like-Kind Exchange, Capital Gains Tax, Agricultural Land, Land Economics/Use, Public Economics, Q15, H24,

    Ethical Issues in Tax Practice

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    Maximizing ecological and evolutionary insight in bisulfite sequencing data sets

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    Genome-scale bisulfite sequencing approaches have opened the door to ecological and evolutionary studies of DNA methylation in many organisms. These approaches can be powerful. However, they introduce new methodological and statistical considerations, some of which are particularly relevant to non-model systems. Here, we highlight how these considerations influence a study’s power to link methylation variation with a predictor variable of interest. Relative to current practice, we argue that sample sizes will need to increase to provide robust insights. We also provide recommendations for overcoming common challenges and an R Shiny app to aid in study design

    Radiation-Induced Magnetoresistance Oscillations in a 2D Electron Gas

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    Recent measurements of a 2D electron gas subjected to microwave radiation reveal a magnetoresistance with an oscillatory dependence on the ratio of radiation frequency to cyclotron frequency. We perform a diagrammatic calculation and find radiation-induced resistivity oscillations with the correct period and phase. Results are explained via a simple picture of current induced by photo-excited disorder-scattered electrons. The oscillations increase with radiation intensity, easily exceeding the dark resistivity and resulting in negative-resistivity minima. At high intensity, we identify additional features, likely due to multi-photon processes, which have yet to be observed experimentally.Comment: 5 pages, 3 figures; final version as published in Phys Rev Let

    Microwave Conductivity due to Scattering from Extended Linear Defects in d-Wave Superconductors

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    Recent microwave conductivity measurements of detwinned, high-purity, slightly overdoped YBa2_{2}Cu3_{3}O6.993_{6.993} crystals reveal a linear temperature dependence and a near-Drude lineshape for temperatures between 1 and 20 K and frequencies ranging from 1 to 75 GHz. Prior theoretical work has shown that simple models of scattering by point defects (impurities) in d-wave superconductors are inconsistent with these results. It has therefore been suggested that scattering by extended defects such as twin boundary remnants, left over from the detwinning process, may also be important. We calculate the self-energy and microwave conductivity in the self-consistent Born approximation (including vertex corrections) for a d-wave superconductor in the presence of scattering from extended linear defects. We find that in the experimentally relevant limit (Ω,1/τTΔ0\Omega, 1/\tau \ll T \ll \Delta_{0}), the resulting microwave conductivity has a linear temperature dependence and a near-Drude frequency dependence that agrees well with experiment.Comment: 13 pages, 7 figure

    Microwave conductivity of a d-wave superconductor disordered by extended impurities: a real-space renormalization group approach

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    Using a real-space renormalization group (RSRG) technique, we compute the microwave conductivity of a d-wave superconductor disordered by extended impurities. To do this, we invoke a semiclassical approximation which naturally accesses the Andreev bound states localized near each impurity. Tunneling corrections (which are captured using the RSRG) lead to a delocalization of these quasiparticles and an associated contribution to the microwave conductivity.Comment: 8 pages, 4 figures. 2 figures added to previous versio

    Transport properties in the d-density wave state: Wiedemann-Franz law

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    We study the Wiedemann-Franz (WF) law in the d-density wave (DDW) model. Even though the opening of the DDW gap (W0)(W_{0}) profoundly modifies the electronic density of states and makes it dependent on energy, the value of the WF ratio at zero temperature (T=0) remains unchanged. However, neither electrical nor thermal conductivity display universal behavior. For finite temperature, with T greater than the value of the impurity scattering rate at zero frequency γ(0)\gamma(0) i.e. γ(0)<TW0\gamma(0)<T\ll W_{0}, the usual WF ratio is obtained only in the weak scattering limit. For strong scattering there are large violations of the WF law.Comment: 1 figur
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